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A Skeptical Look At The Multiverse
sjanich writes "The NY Times has a short, interesting article on multiverse theory. The author, Paul Davies, writes: 'This idea of multiple universes, or multiple realities, has been around in philosophical circles for centuries. The scientific justification for it, however, is new.' It is quite an interesting read. The author is a Physicist and pretty good science writer." Davies is not kind to the multiverse theory.
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http://www.hedweb.com/everett/everett.htm
Taking the multiverse theory at face value, therefore, means accepting that virtual worlds are more numerous than "real" ones. There is no reason to expect our world -- the one in which you are reading this right now -- to be real as opposed to a simulation.
I mean, what's the problem with this? Until we find evidence to the contrary, it remains a distinct possibility. And it borders on the realm of so-what. Is the knowledge that you're actually a participant in a very large simulation going to change how you live your life?
I mean, are you annoyed that when you fall, you accelerate at exactly 9.8 m/s^2 (in a vacuum) towards the center of the earth, without fail? Those unimaginative programmers...
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
Davies refers to, but never explicitly states one particular point: Most of the multiverse theories are inherently untestable, because we're completely isolated from the other universes. These are theories that don't predict or even suggest anything. How meaningless can you get?
This is a good general point. Solipsism is uninteresting. Subjectivism & deconstructivism are often taken to similar absurd extremes by stupid people, including respected critics.
He makes the analogy between theology & these scientific non-explanations. Religion is personally very meaningful, but metaphysics isn't science. Consequently a classic metaphysical question, "How many angels can dance on the head of a pin?" is the canonical meaningless question.
The word that springs to mind is sophomoric. It reminds me of High School, when one friend asked another "What if you're really insane & just dreaming all of this?" The answer was of course, "So what? You've gotta pretty much live your life the same way anyway."
Assembly is the reverse of disassembly.
Why is nature so ingeniously, one might even say suspiciously, friendly to life?
Well, this is one to ponder, granted that you consider life to be basically an earthbound form or entity. It always amuses me that there is talk about whether this place or that could support life. Just because we, as earthbound beings, rely on certain conditions to live, who is to say that other lifeforms would live in something that we'd consider completely destructive to our own very nature. How do we know that there aren't life forms out there that don't depend on breathing molten gold in the same way we need to breathe oxygen? Or to take it even farther, who says they need to breath at all?
But to come back on topic, I think that the multiverse theory is a very interesting one. I think it's possible. Why? Because it's interesting that way. =0)
*slight crashing sound*
Everywhere he says life could not exist in any other universal properties and constants should be modified to state "life as we know it."
quote:
Life would probably be impossible with more (or less) than three dimensions to work with, so our seeing three is then no surprise. Similar arguments apply to other supposedly fixed properties of the cosmos, such as the strengths of the fundamental forces or the masses of the various subatomic particles.
Why exactly is life impossible with more than 3 dimensions? He subscribes to the fundenmental flaw that all science fiction writers subscribe to: all alien life forms breath, walk on legs, and "see" through eyes. Sure, it's hard to change a human actor on a movie screen by too much, but the world of books and pages ought to be able to create something better.
I also agree with the other post that says, paraphrased, if we live in a giant simulation, does that make existance different? If you can't get out of, or control the simulation, what difference does it make? I, for one, am not worried about hyperintelligence alien giants looking at me showered naked, and the like.
Along those same lines, if we can eventually create computer simulations with sentiant beings, why can we not create a universe with different parameters and force life to exist within it?
Lastly, if we can't get out of this universe into another one, what difference does it make? And if we somehow break the barrier and jump universes, the link between them makes them one universe with localized properties doesn't it?
-Ryan
AUWYHSTOT (Acronyms are Useless When You Have to Spell Them Out Too)
I was just reading the "article" and getting more and more annoyed with how clueless and full of unfounded and dumb opinions it was. . . Then I looked at the big warning label on top, "Op-Ed" this is an Editorial! This should not be in the "Science" heading it's just creationist political opinion. It's by a philosophy professor not a scientist. As an op-ed it isn't even a well argued one, no facts no educated opinion even.
It is worthwhile to point out that cosmological
diversity is only one kind of "multiverse" theory.
In it, all of the various universes are embedded
in a larger space. Such theories are not therefore
unscientific, in the sense of being intrinsically
unfalsifiable, or unverifiable: Because the various
universes have topological relation to one another,
there is a continuum of existence connecting them,
and they may interact in yet unforseen ways. Our
current inability to design experiments to detect
such interactions is merely an artifact of
ignorance.
But there are many other forms of ontological
multiplicity which do not involve topological
continuum. The outstanding example is the
Everett interpretation of quantum mechanics.
In that theory, rather than the actual state of
affairs in the universe being the sole real
instantiation of the phi wavefunction, created
by the act of observation (as in the classical
Copenhagen interpretation of Bohr et al), the
quantum wave function is considered to be a
representation of the distribution of an infinite
multiplicity of alternatives, all equally "real".
I find the Everett interpretation to be much
preferrable, on several grounds, not the least
of which is that it is consistent with the
mathematical concept of probability distribution
in a way which the Copenhagen interpretation is
not, but others disdain
it because it implies the real existence of
entities which are not, so they say, in principle,
detectable. Again, this complaint fails because
it is an argument from ignorance: The current
inability, at a given level of human understanding
and technology, to design a verifying or falsifying
experiment, does not relate to the truth or falsity
of the hypothesis. Cophenhagenists are quite
comfortable supposing that unseen cats are undead,
and any truth not currently known is not yet true.
I think this is a much larger leap of faith than
is needed to create a working understanding.
-I like my women like I like my tea: green-
Science: A Skeptical Look At The Universe
The NY Times has a short, interesting article on universe theory. The author, Paul Davies, writes: 'This idea of single universe, or single reality, has been around in philosophical circles for centuries. The scientific justification for it, however, is new.' It is quite an interesting read. The author is Physicist and pretty good science writer." Davies is not kind to the universe theory.
this is neat, especially when you look at some more current work on virtual particles, and virtual particle clusters. Then when you apply time dialation and distortion to a virtual particle cluster its amazing what happens. Well, that can be 20 billion years in the blink of an eye as compared to the actual particles surrounding the virtual universe.
this is not a sig.
This article annoyed me, because it felt like the author reasoned backwards from his own prejudice. It seemes as if he has an actual abhorence of the very idea of multiple universes, perhaps because that would make our own little universe less than special.
He claims multiverse theories are all by nature unverifiable. Hogwash. Off the top of my head, I can think of at least one type of multiverse theory that would be. Scientists now speculate that we may live on a higher-dimensional 'sheet' or brane, as they call it, with others along side ours. Gravity from the nearby branes affects ours and vice versa. This effect could possibly be calculated and tested. Just because the theories can't currently be verified doesn't mean that they are without merit.
He seems to have a special problem with there being more virtual universes than real ones, but it makes no sense. Even if there was only one universe, there would likely be more than one virtual universes within it. We still would have no way of knowing if we were in the original, 'real' universe, or a virtual knock-off.
He also claims that multiverse theories require gods or creators at all levels and scales. This is where his religious bias becomes utterly apparant. He is uncomfortable with the idea of there not being one true creator from which everything else springs. He claims the idea of infinite regress of creator/created dyads is a type of logical fallacy known as reductio ad absurdum, which means reduction to the ansurd, but it is not.
Reductio ad absurdum is disproof of a proposition by showing that it leads to absurd or untenable conclusions. His "untenable conclusions" are a radically revised relationship between the Devine and Its human creations. News flash: just because you find something absurd doesn't mean it isn't true. And just because a scientific theory requires you to revise your idea of some personal creator-god doesn't mean that theory is absurd. Reductio ad absurdum is more properly used when you show that, for instance, your opponants argument prooves that up is down, or some other obvious nonsense.
If any theory is unverifiable, it is the theory of a personal creator-god. If it was verifiable, we wouldn't need faith.
This is anti-scientific religious hogwash, not a reasoned scientific article. What really pisses me off is that the author, Paul Davies, is a professor of natural philosophy, and should know better than to misuse terms like reductio ad absurdum.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Til we had the toys to play with quantum physics, all this multi-verse stuff was just about as useful as saying "God made it that way."
Now we know something funny is going on with those itty-bitty bits of matter, but don't leap to conclusions because, because that's bad. And, um, this could all be like the Matrix inside the Matrix. So, be careful.
No supporting data is available, but these ideas seem to make sense so I'm getting them published.
The existence of intelligent life does require the universe to be large and complex. The multiverse interpretation demonstrates a related point: the probability of intelligent life arising in this universe might be low, or even very low. You don't need the multiverse interpretation to work this out, but it does make it a lot clearer. The ET searchers often express the assumption that our existence shows that intelligent life is likely to have a probability greater than one (because here we are). The fallacy that the size/complexity of the universe (which came first) caused intelligent life (which came later) is an easy mistake. You really need the multiverse interpretation to see that it is a selection effect fallacy. Note that the multiverse interpretation doesn't have to be "true" to fill this role, just one consistent way of looking at the issue.
Taking the multiverse theory at face value, therefore, means accepting that virtual worlds are more numerous than "real" ones.
Even is this were a reason to be concerned (even if it's true, what are you going to do about it?), what the hell does this have to do with the multiverse theory? How is this virtual world conundrum dependent on it? Can't we start the whole virtual world chain of deception right here on Earth, without anybody else's assistance anyway? Why do we have to believe in the multiverse theory in order for the idea of this reality being virtual to be true?
The rest of his argument is a bit much for a Saturday afternoon, anyway. There is an article in Scientific American that talks about this very topic. There are many theories about the multiverse, and only some assume different basic laws. One of them allows for different constants , but occuring with the same laws (i.e., everything works exactly the same, except, oh, I don't know, the weak nuclear force is 2% weaker).
Ah, it's nice out, I quit the rant now. But this shouldn't have gotten past the NyC editors, much less Slashdot's. His argument is since we can't confirm it by seeing it, it's pointless. Heh, most of physics today falls into that realm.
This isn't a case of anthropomorphism or earth-centrism or anything like that. It's an outcome of basic physics (it does take into account that physics may be different in other universes, though).
To take a simple example at the grossest level: imagine a universe in which symmetry broke in such a way that instead of three macroscopic spatial dimensions resulting, there were only two. A two-dimensional universe would be incapable of hosting structures of very significant complexity such as multicellular lifeforms. There would be strict limitations on size becaues a 2-D lifeform cannot possess any kind of internal transport system for alimentation or circulation - it would simply fall apart (try drawing one and see how internal channels effectively divide the creature into pieces).
Four dimensional universes (and higher order dimensional spaces) also have topological problems which would make life difficult though you'll have to look those up for yourself.
Even in three dimensional universes, very slight modifications to the relative strength of the four fundamental post-symmetry-breaking forces would make the universe appear very different.
There will be universes composed entirely of radiation - but radiation does not interact well enough to form structures spontaneously.
There will be universes where stars shine but never explode, thus elements heavier than helium are never released from their cores - and you can't get interesting chemical reactions from just hydrogen and helium.
There will be many dark universes where star-sized agglomerations of matter simply do not ignite at all, thus energy cannot be concentrated sufficiently enough in any one place to fuel a biosphere.
Even if you had hot stars and an interesting array of elements it may still be devoid of life if there was no possible *simple* (and thus common) combination of those elements available to provide a molecule like water - slightly more than weakly polar, which remains liquid at a range of useful temperatures (warm enough to enable chemical reaction at a significant rate, cool enough to allow stable reaction products).
It's all very well to postulate "energy beings" or Horta-style silicon-based lifeforms but basic physics just doesn't make these very likely. There are strong practical reasons why all life on Earth is based on water and carbon compounds. There may be other constellations of physical laws which could generate a universe complex enough to support life, but there are far, far more that couldn't, no matter how good your imagination is.
The May issue of Scientific American contains a much more in-depth article on parallel universes, which has enough points in common that it might have inspired the op-ed piece.
Teaser for the article is here. To get the whole thing, you either have to have a subscription or wait until next month.
The gist of it is as follows:
In principle, these other "universes" can interact with our own, but in practice they're far enough away that it doesn't matter. Physical laws are likely similar.
Re. an infinite universe, the article states that a finite universe would leave artifacts in the cosmic microwave background that weren't seen.
These parallel universes are utterly unreachable, as the space between them a) exists in a different coordinate system that puts it in our past from our point of view, and b) is expanding exponentially quickly, dragging other universes away from ours at mind-boggling speed.
As far as I understand it, interaction between these universes wouldn't be possible without violating some of the ground rules involved (the history tree could be thought of as a state transition diagram for all possible states of a closed system; if it's closed, it can't interact with anything else).
If you call this a "real" universe, then Everquest and the reality hosting the United Federation of Planets are also real universes. It depends on your point of view (and what you mean by "real" in this context).
The existance of "universes" of the first type is certain if the universe is infinite, from information theory arguments. The infinite or non-infinite nature of the universe is something that can be empirically tested (though the final test - waiting for every part of it to come within our observation horizon - is impractical).
The existance of the second type of universe hinges on the nature of the scalar fields proposed in the various inflationary models. In principle, this is testable, either by recreating the energies required or by observing distant parts of the universe that are undergoing inflation.
The existance of the third type of universe is not testable, due to the requirement for closed systems. So it's pretty much a moot point.
The existance of the fourth type of universe is a metaphysical question, whose answer depends on what you mean by "exist".
The full article has a lot of additional discussion, and pretty pictures. By all means pick up a copy, if the topic interests you.
> > Why is nature so ingeniously, one might even say suspiciously, friendly to life?
> Well, this is one to ponder, granted that you consider life to be basically an earthbound form or entity. It always amuses me that there is talk about whether this place or that could support life. Just because we, as earthbound beings, rely on certain conditions to live, who is to say that other lifeforms would live in something that we'd consider completely destructive to our own very nature. How do we know that there aren't life forms out there that don't depend on breathing molten gold in the same way we need to breathe oxygen? Or to take it even farther, who says they need to breath at all?
Also, when people start arguing that the universe is uniquely suited for life it is useful to ask them what percentage of the universe is actually hospitable to life AWKI.
A thin crust at the surface of a few planets, out of the entire volume of the universe? It looks to me like the universe was "designed" for something else altogether, and life found a few rare, small cracks to hide in. As well to say that the lobby of a fine hotel was designed to harbor dust particles.
Sheesh, evil *and* a jerk. -- Jade
Paul Davies is a religious person. And so when there are two competing theories, one of which includes his ideals of religion, and one which does not, he will choose the first if there is no other evidence given. The reason that the multiverse theory is postulated is to give a kind of evolutionary account of the cosmology of the universe. Who knows if there are other universes, or if they are anything like our own? We certainly will never know.
But Davies' favored alternative is a much less viable option. To explain away the existence of our world with something that's even more complicated, such as God, is no explanation at all. Explanations reduce complex things to simple things. And if God can create something as complex as the universe, he must clearly have at least that much complexity within Himself.
We've seen this conflict before. Look at these well designed humans! How could they have possibly arrived upon this Earth? Surely only a being as complex as God could have accomplished such a wonderful feat! This was the great argument of the last two centuries, and the consensus is that evolution and natural selection form a much better explanation than divine creation.
And I guess not much has changed since then. Look at this well designed universe! If things were only slightly different, no life could have been formed at all. Surely there is a divine influence at work! But whenever you drop something like God into your explanation, you've only made your job harder. Now instead of explaining life or the universe, you have to explain the existence of this vastly powerful and mysterious creature that made it all take place.
The other possibilities, though possessing many flaws, are much more plausible. It's much more plausible to think that many universes were created, and that only those suitable for life actually developed life, than it is to think that there is only one universe, whose existence can only be explained though divine creation.
I understand it lets you get away with not having to treat the observer of the quantum event as seperate and somehow special.
This seems less arbitrary to me... Copenhagen's interpretation makes a big assumption about the role of the observer.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
This isn't a case of anthropomorphism or earth-centrism or anything like that.
Yes it is. You made a ludacris number of false statements and assumptions.
Two-dimensional organisms for starters: Just because you can't have a conventional mouth-alimentary_canal-anus is no evidence that you cannot have a complex multicellular organism. (Not that life needs to be multi cellular, or even cellular at all). Even if we take the silly assumption that life requires a "conventional" digestive system it could still use an adsorption type system, a vacuole type system, or a two-way digestive system like hydras have - one opening acts as both mouth and anus.
Nor does 2-d prevent circulation. The creature could be formed of concentric donuts with circulation around them. They can even have complex structures that "cut them in peices" if they have transient connections between them. Think of the human circulatory system, except imagine that the valves in the various arteries/veins acted like hooks when they closed. This could even allow two completely different circulatory systems to cross through each other in an alternating pulsing manner. The valves would alternately close/link keeping the two circulations isolated. Seperate pieces could also be held together with interlocking shapes like like this. Note that they are held together, yet there is a gap for a circulation channel. Pieces could be held together in a variety of other ways.
Four dimensional universes (and higher order dimensional spaces) also have topological problems
LOL, what makes you think those topological differences are a "problem" for life? Higher dimentional life would probably make similar comments that 3-dimentional life was "impossible".
Even in three dimensional universes, very slight modifications to the relative strength of the four fundamental post-symmetry-breaking forces would make the universe appear very different.
Yes, different. Is is pure anthropomorphism or earth-centrism to assume "different" is any sort of argument.
There will be universes composed entirely of radiation - but radiation does not interact well enough to form structures spontaneously.
Ok, lets assume that is a reasonable example of what the another possabile universe might be. In our universe intense/high energy radiation does in fact interact. I think it is reasonable to expect the radiation in such a universe would likely be even more intense and energetic. This would increase the interaction. It is not unreasonable to think that any change in the laws of physics that resulted in an all radiation universe would also increase the strength of these interactions, or even result in new kinds of interactions. You have absolutely no idea how such a universe would function, how can you even begin to say that it is incapable of supporting life?
There will be universes where stars shine but never explode, thus elements heavier than helium are never released from their cores - and you can't get interesting chemical reactions from just hydrogen and helium.
.
.
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molecule like water - slightly more than weakly polar, which remains liquid at a range of useful temperatures
That entire section is nothing more than a DEFINITION of anthropomorphism! You are ASSUMING that life has to resemble us! You might as well claim that life has to be made from DNA and must have two eyes and a nose.
a universe complex enough to support life, but there are far, far more that couldn't, no matter how good your imagination is.
It doesn't matter how good or bad anyone's imagination is. We can imagine forms of life that don't exist and life can take forms that we haven't thought of.
What are the requirements of life? I would speculate the requirement is merely a system rich/complex enough to contain patterns which are capable of creating copies of themselves. The medium the patteren
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
A Brief History of the Multiverse
By PAUL DAVIES
New York Times, April 12, 2003
http://www.nytimes.com/2003/04/12/opinion/12DAVI.h tml?pagewanted=print&position=top
SYDNEY
Imagine you can play God and fiddle with the settings of the great cosmic machine. Turn this knob and make electrons a bit heavier; twiddle that one and make gravitation a trifle weaker. What would be the effect? The universe would look very different -- so different, in fact, that there wouldn't be anyone around to see the result, because the existence of life depends rather critically on the actual settings that Mother Nature selected.
Scientists have long puzzled over this rather contrived state of affairs. Why is nature so ingeniously, one might even say suspiciously, friendly to life? What do the laws of physics care about life and consciousness that they should conspire to make a hospitable universe? It's almost as if a Grand Designer had it all figured out.
The fashionable scientific response to this cosmic conundrum is to invoke the so-called multiverse theory. The idea here is that what we have hitherto been calling "the universe" is nothing of the sort. It is but a small component within a vast assemblage of other universes that together make up a "multiverse."
It is but a small extra step to conjecture that each universe comes with its own knob settings. They could be random, as if the endless succession of universes is the product of the proverbial monkey at a typewriter. Almost all universes are incompatible with life, and so go unseen and unlamented. Only in that handful where, by chance, the settings are just right will life emerge; then beings such as ourselves will marvel at how propitiously fine-tuned their universe is.
But we would be wrong to attribute this suitability to design. It is entirely the result of self-selection: we simply could not exist in biologically hostile universes, no matter how many there were.
This idea of multiple universes, or multiple realities, has been around in philosophical circles for centuries. The scientific justification for it, however, is new.
One argument stems from the "big bang" theory: according to the standard model, shortly after the universe exploded into existence about 14 billion years ago, it suddenly jumped in size by an enormous factor. This "inflation" can best be understood by imagining that the observable universe is, relatively speaking, a tiny blob of space buried deep within a vast labyrinth of interconnected cosmic regions. Under this theory, if you took a God's-eye view of the multiverse, you would see big bangs aplenty generating a tangled melee of universes enveloped in a superstructure of frenetically inflating space. Though individual universes may live and die, the multiverse is forever.
Some scientists now suspect that many traditional laws of physics might in fact be merely local bylaws, restricted to limited regions of space. Many physicists now think that there are more than three spatial dimensions, for example, since certain theories of subatomic matter are neater in 9 or 10 dimensions. So maybe three is a lucky number that just happened by accident in our cosmic neighborhood -- other universes may have five or seven dimensions.
Life would probably be impossible with more (or less) than three dimensions to work with, so our seeing three is then no surprise. Similar arguments apply to other supposedly fixed properties of the cosmos, such as the strengths of the fundamental forces or the masses of the various subatomic particles. Perhaps these parameters were all fluke products of cosmic luck, and our exquisitely friendly "universe" is but a minute oasis of fecundity amid a sterile space-time desert.
How seriously can we take this explanation for the friendliness of nature? Not very, I think. For a start, how is the existence
Use my userscript to add story images to Slashdot. There's no going back.
and one I had not heard before.
I think the real point is, not that he finds the idea of us living in a "simulation" abhorrent or impossible, but that any theory from which such a conclusion logically follows is something that cannot be considered scientific - such a theory is exactly equivalent to a religious doctrine in which unexplained events are attributed to the supernatural (unexplained "miraculous" events in our universe could be just defects in the simulation, or even deliberate effects caused by the simulators, after all).
And that sort of thing just flies in the face of centuries of doctrine and methodology in science, about what science really is.
I think it's an interesting argument; I find myself somewhat inclined to agree - depending on the type of multiverse we're talking about, anyway.
Energy: time to change the picture.
The correct answer to "What if you people are all a dream of mine?" is to smack the questioner in the side of the head. What's he going to do, get mad at one of his dreams?
There may be other constellations of physical laws which could generate a universe complex enough to support life, but there are far, far more that couldn't, no matter how good your imagination is.
Since my imagination can think of an infinite number of variations on any set of physical laws, how do you quantify "more"?
First, an arbitrarily detailed simulation of a universe would require all of the resources of the host universe - so it might as well be a real universe, and there is no multiplication effect. Since we (and by we I mean I ;-) have no evidence of this universe being a simulation, I assume that if it is a simulation it must be an arbitrarily detailed one.
Second, a simulated universe with limited detail would not spawn child universes. Oh, the inhabitants of the simulated universe might think they had started their own simulations, but back in the real universe the computer running the simulation they inhabit would have no reason to run the secondary simulations - it only needs to produce perceptions for the inhabitants of the first simulation. So again, there is no proliferation of virtual universes that would make it more likely for a conscious being to be in a simulation than in a real universe.
Note that I am not discounting the sort of simulation required for solipsism - it would come under the second sort of simulation.
If we were ants living on a Rubik's cube, differential geometry would be a little more confusing.
... those socks that vanish every time I do laundry have to go somewhere.
------ The only greater hazard to your liberty than n politicians is n+1 politicians.
Here is part two (its in two parts): hopefully this one will display propely: A Brief History of the Multiverse (Page 2 of 2) Extreme multiverse explanations are therefore reminiscent of theological discussions. Indeed, invoking an infinity of unseen universes to explain the unusual features of the one we do see is just as ad hoc as invoking an unseen Creator. The multiverse theory may be dressed up in scientific language, but in essence it requires the same leap of faith. At the same time, the multiverse theory also explains too much. Appealing to everything in general to explain something in particular is really no explanation at all. To a scientist, it is just as unsatisfying as simply declaring, "God made it that way!" Problems also crop up in the small print. Among the myriad universes similar to ours will be some in which technological civilizations advance to the point of being able to simulate consciousness. Eventually, entire virtual worlds will be created inside computers, their conscious inhabitants unaware that they are the simulated products of somebody else's technology. For every original world, there will be a stupendous number of available virtual worlds -- some of which would even include machines simulating virtual worlds of their own, and so on ad infinitum. Taking the multiverse theory at face value, therefore, means accepting that virtual worlds are more numerous than "real" ones. There is no reason to expect our world -- the one in which you are reading this right now -- to be real as opposed to a simulation. And the simulated inhabitants of a virtual world stand in the same relationship to the simulating system as human beings stand in relation to the traditional Creator. Far from doing away with a transcendent Creator, the multiverse theory actually injects that very concept at almost every level of its logical structure. Gods and worlds, creators and creatures, lie embedded in each other, forming an infinite regress in unbounded space. This reductio ad absurdum of the multiverse theory reveals what a very slippery slope it is indeed. Since Copernicus, our view of the universe has enlarged by a factor of a billion billion. The cosmic vista stretches one hundred billion trillion miles in all directions -- that's a 1 with 23 zeros. Now we are being urged to accept that even this vast region is just a minuscule fragment of the whole. But caution is strongly advised. The history of science rarely repeats itself. Maybe there is some restricted form of multiverse, but if the concept is pushed too far, then the rationally ordered (and apparently real) world we perceive gets gobbled up in an infinitely complex charade, with the truth lying forever beyond our ken. Paul Davies, professor of natural philosophy at the Australian Center for Astrobiology, is author of "How to Build a Time Machine." Previous | 1 | 2 Einstein Was Right on Gravity's Velocity (January 8, 2003) $ 3 Nobels for Solving Longstanding Mysteries of the Cosmos (October 9, 2002) $ Radio Telescope Proves A Big Bang Prediction (September 20, 2002) $ Studies Suggest Unknown Form of Matter Exists (July 31, 2002) $ Find more results for Space and Physics . Doing research? Search the archive for more than 500,000 articles: It's easy to follow the top stories with home delivery of The New York Times newspaper. Click Here for 50% off. Home | Back to Opinion | Search | Corrections | Help | Back to Top Copyright 2003 The New York Times Company | Privacy Policy Topics Alerts Space Physics Create Your Own | Manage Alerts Take a Tour Sign Up for Newsletters
I wonder what the timecube guy has to say about multiverses?
Well argued, and I have a lot of sympathy with some of the points you made, but there must be a reason that these systems appear only in relatively simple life forms on Earth and that organisms large enough to exhibit complex behaviour don't utilize them. It would be reasonable to assume that it is more difficult for such lifeforms to progress beyond a certain size.
Of the more outlandish sytems you envisage the best one can say is that they are not absolutely impossible. But they must be relatively difficult to eveolve, or else nature would not have avoided them so completely here on Earth.
With regard to the topology of spacetime, as another poster reminded me, even-numbered dimensionality would preclude stable orbits so either matter would not accumulate at all (would remain highly dispersed gas & dust) or it would all collapse into black holes, or lumps would form and then wander around erratically. Stars are required to provide an energy gradient, and planets are required to sometimes provide a collection of matter at a suitable place in that gradient. These im turn require suitably balanced fundamental forces and the right number of dimensions.
Calm down, eh? I am assuming nothing of the sort. I am just reminding you that life based on matter at what we would call reasonable temperatures combines chemically, that is by atoms coming into close proximity and exchanging and sharing electrons. For a whole number of reasons too numerous and complex to go into here this generally requires a suitable liquid solvent for things to proceed at a useful rate. Even where catalyst surfaces containing aluminate etc. are involved. Water is uniquely suited for this purpose because it is both polar and liquid at "room" temperature. Fortunately (and the anthropic principle comes into play here) water is relatively abundant in our universe because it requires only hydrogen (the most abundant element) and oxygen (which is released by supernovae in large quantities).
The significance of this is that water's unlikely properties are only possible because the relative strengths of the four fundamantal forces lie within a very narrow range. It follows that most differently-built universes would not provide a substance like it.
True, true, true.
Not true. Our universe is not necessarily representative. eg. a one-dimensional universe woule necessarily support less complexity than does ours. A two-dimensional one also for the rea
If you buy into the "Schroedinger's Cat" thought experiment, then you pretty much have to accept that there are multiverses.
/. headline "Scientist murdered following insane Cat experiment!" and another boring day of RIAA news.
In Schroedinger's experiment, there is a cat in a box that is either killed or not killed depending on the result of some test of quantum superposition. The cat remains in this hybrid state of being dead or not dead until someone opens the box to 'observe' the event. I think most scientists believe this - and it's being demonstrated right now in things like Quantum Computers.
That's all well and good - but suppose it's a human in the box? They are simultaneously both alive and dead - for that person, there are two parallel universes - one in which they are alive and the other in which they are dead.
Now, you can extend the cat experiment outwards. Inside the room where the cat experiment is being conducted is the Mad Scientist and his assistant (who happens to be a Cat lover). If the cat in the box dies, the assistant kills the Mad Scientist in a fit of rage...if the cat is OK, nothing happens.
So, for someone standing outside the lab, we have a second Schroedinger experiment. Only when the lab door is opened will we know the state of the Mad Scientist - is he dead or alive? Since that state directly depends on the quantum superposition, he's in the same hybrid state as the cat was.
By extension, the entire planet earth is superposed between the
There are potentially VAST numbers of these 'superposition' experiments going on throughout the earth - none of which are resolved until some alien race happens to 'observe' us. Then, the aliens in turn are in a super imposed state that is not resolved until something also observes their reaction to that resolution.
So, there must be an almost infinite number of superimposed universes all waiting for some ultimate resolution. But life goes on - and we don't *feel* any different for being in a superimposed state.
It follows then - directly from Schroedinger - that there are an infinite number of universes with all possible outcomes of all possible events happening in them.
Now here is the biggie: If you also believe in the 'strong anthropic principle' - then I exist in *this* universe because it just happens to be one of the universes where I didn't die in a car crash last week. If that's true then I must live forever. There will always be an infinite number of universes in which I miraculously avoid every possible accident - where immortality is somehow invented before I get too old.
By definition, that's always going to be the universe I'm living in right now because I have to be here in order to observe it.
OK - now I have a headache.
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Of the more outlandish sytems you envisage the best one can say is that they are not absolutely impossible.
You claimed to give reasons 2-d life was impossible. I proved that claim false with counter examples. I never claimed that those are the systems 2-d life would actually use. The point is that there are a wide variety of ways life could overcome each of your objections. Life is far more "creative" at problem solving than I am and it would probably come up with far better systems than I described.
But they must be relatively difficult to eveolve, or else nature would not have avoided them so completely here on Earth.
That's kind of like looking at the ocean and saying feathers must be difficult to evolve. Life in the ocean "avoids" feathers because feathers are not the best solution in an ocean enviornment. Life on earth evolved in the manner most suitable for earth. Life in a 2-d enviornment would evolve in the manner most suitable for a 2-d enviornment.
even-numbered dimensionality would preclude stable orbits
Yes, I'm familiar with that result. It proves that a 4-d universe would not produce anything resembling solar systems in our universe. But the question is not "can it support conventional solar systems?", the question is "can it support complex systems?". Given a 4-d big bang, can you tell me how that universe will develop? What structures and systems it will produce? We can hardly even begin to speculate, so how can you possibly conclude that you've shown it cannot support life?
Stars are required to provide an energy gradient, and planets are required to sometimes provide a collection of matter at a suitable place in that gradient
Any one of the following points is adaquate to strike down that argument:
(1) Stars are not required to provide an energy gradient. There are all sorts of energy gradients.
(2) Planets are not required in order to have a complex system.
(3) You have not proven that you cannot have a mass collection at some distance from a star in 4-d. I can conceive at least 5 mechanisms by which it could occur. If did occur it would probably be through a mechanism I haven't thought of. I have no idea how a 4-d universe would actually organize itself.
(4) You are making anthropomorphic assumptions about what would be a "suitable" place within the gradient. Complex systems occur within our sun. Consider that a 4-d sun would have a 3-d "surface". Our entire universe could conceivably be a limited view of the processes on the surface of a 4-d star or black hole. Each fundamental particle could be a magnetic field line or vortex in that surface. A complex system can be an emergent property of another complex system. A single 3-D quark could be an emergent representaion of a million mile 4-D vortex on the surface of a star. Just like an orange is an emergent representaion of trillions of quarks.
I am assuming nothing of the sort.[Making anthropomorphic assumptions] I am just reminding you that life based on matter at what we would call reasonable temperatures.
Yes you are. Sure liquid water and carbon chains make for a good complex system, but it is antropomorphic to assume it is the only good complex system. It is irreleveant what we find to be a "reasonable" temperatures.
most differently-built universes would not provide a substance like [water]
So? It is entirely anthropomorphic to assume water is a requirement. Are you going to claim that there are no complex systems that do not involve water? Water itself is nothing more than an emergent sproperty of the complex system of molecules which is nothing more than an emergent property of the complex system of atoms which is nothing more than an emergent property of the complex system of electrons+protons+neutrons whic is nothing more than an emergent property of quarks, leptons, gluons, virtual particle, which are no more than an emergent property of perhaps one dimentional strings vibrati
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Imagine that your car begins making a strange knocking sound when you brake. You take your car into the autoshop to find out what's causing the problem. Without even looking under the hood, the mechanic explains that the reason your car is making the sound is because there are infinitely many universes with different versions of you and your car, and you just happen to live in the universe where the car began making a knocking sound. Odds are, you'd look for another mechanic. The multiverse theory essentially uses the same logic to explain (or explain away) features of the universe such as the gravitation or planck constant. As such, its basically a huge non-explanation. Regardless of Davies particular bias, his main point is that the theory is practically devoid of explanation and is about as meaningful as saying "God did it". When Davies invokes the term "falsifiable", he isn't claiming that there couldn't be evidence to support it, but rather there could never be a way to disprove the theory. The lack of criteria for falsifying multiverse theories is problematic because there could be other, more fruitful theories that explain the same observations as a particular version such as Brane Theory. Returning the above example with the mechanice, compare the two rivals theories for the noise: a) infintely many universes with different parameters for the car's noise level when brakes are applied. b) the brake-pads are worn out. A is just as valid a theory as B; the difference is, you can disprove B, and apply B to tell you something about the car (it needs new brake pads). Which theory do you think is better? For a final bit of flame; yeah, maybe people dislike multiverse theories because they mean are universe isn't "special"...but my feeling is that multiverse theories have such appeal is because they're a neat sci-fi prop, not because they have any real value.
Five? I'd genuinely like to hear the details of these mechanisms. If you can model processes in five-dimensional spacetime in your head you must be the cleverest person on this planet. Either that or not actually from this planet.
OK, I follow you...
Er..OK, I'm still with you...
Whoa. For this to be any more credible than lunar green cheese, somebody would have to work out a physical system in that reference frame which is at least capable of explaining the precise properties and behaviour of quarks in our reference frame. Has this been done?
I have to disagree. With the physics we have, we can't meaningfully conceptualize a universe based on anything other than space, time, matter and energy, let alone "life" based on anything other than those. And of those, matter has to be a principal requirement since it is the only one that interacts, self-assembles into interesting structures and retains state in a useful way.(*see footnote)
Matter of course only behaves in this way under a strictly limited temperature range. Hence it is important for this temperature range to be available.
All true but uterly beside the point - you're thinking way too deeply about this.
With regard to the stuff about water, you miss my point I think. I'm not saying a life bearing universe has to have water, I'm saying in order to support life based on matter it needs some substance which fulfils a similar role, and that the extremely unique and unlikely properties of water in our universe make it a reasonable bet that such substances might be rare in other physical systems in general.
I'm guessing your background is in mathematics as you appear to be relying on the "existence proof" - the whole thrust of your argument appears to be that complex systems capable of supporting life are always or almost always possible in any universe because most arrangements are physically capable of supporting complex systems. But I don't wish to dispute that. My argument is only that though you may reason life may still be possible in most weird (to us) universes, it will still be highly improbable. Don't forget that it has to arise spontaneously as well. How the hell is something as organized as a Turing machine going to spontaneously self-generate in a one dimensional universe? Apart from the limited scope for spatial arrangements, opportunities for particles to even change position relative to each other are at least going to be hampered by the fact that they have to move through their neighbours to do so. Yes, don't tell me, there is a way, they can switch positions by quantum tunnelling or switching clothes or something, but the fact is, and this is what seems to escape you, is that the more constraints you heap upon the system the less and less likely it is that life will have time to appear, evolve and become intelligent before that universe ends in whatever manner it is destined to do.
*FOOTNOTE. Different fundamental forces would mean different relative field strengths and so matter
Since the anti-monitor destroyed it in Crisis on Infinite Earths #11 in November of 1985. The fact that people are still speculating about this shows that most physicists probably read such Marvel or Romance comics.
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Ein, Zwei, Drei is German for 1,2,3. Hence Einstein, Zweistein, Dreistein.
****Gfx Scrollbar Special case hit!!*****
I do not want to comment too much, except for
h tm l
a) Life in a 2D universe has to expend much more energy to function due to all the constraints put on it that 3D life does not have. For instance the comlicated set of valves and thingies that one poster envisioned simply takes more effort, and therefore energy, to develop and to operate inside the lifeform. This may not preclude life but it may preclude very complicated life and would at the least make it more difficult to develop. Just as there is more life in the tropics than in the arctic because the conditions are better.
b) Many of the arguments made there deals with macroscopic features of such a universe (ie, on the scale where gravity is significant).
However, if you turn the knob on the strong nuclear force things such as atoms or even protons cannot form. OR are unstable. This would probably preclude life.
However, considering the sheer complexity of the inside of a proton and the extreme difficulty in simulating the quantum chromodynamic interaction inside it one must admit the possibility of other sort of particles forming. Which will lead to a completely different sort of place. The inside of a proton, an (almost) fundamental particle is unbelievably complicated.
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Anyways, a good book which deals in some depth with the subject of physical constraints on life itself is Barrow's "The artful Universe.." This is great read and raises many points to ponder.
http://www.addall.com/Browse/Detail/0316082422.
Btw, his book on the philosophy of mathematics, "Pie in the sky" is also good.
And a question, I've heard this higher dimensions do not allow orbits argument somewhere before. Does anyone have some kind of reference?
The dangers of excessive individualism are nothing compared to the oppressiveness of excessive collectivism
Yikes, this post got kind of long and wordy. I'm too tired to trim it down. Sorry, chuckle.
:)
I'd genuinely like to hear the details of these mechanisms. [mass at some distance from a star in 4-d]
Unstable orbits can be maintained as a stable orbit when an aditional force enters the picture. Some of these "unstable" orbits can be maintained with an amazingly small small additional force. For example in 3-d there are five lagrange points. Three of them are "unstable" points of exactly this type. It only takes a miniscule nudge to maintain them.
Possible forces to stabilize an orbit: (1)Radiation pressure. (2)Solar wind. (3)Magnetic field. (4)Electric charge (the earth carries a sizeable charge). A planet's magnetic field moving through a charged solar wind can produce a (5)magnetohydrodynamic force. (Yes, magnetohydrodynamic is a real word.)
In some situations a (6)many-body system may be stable where a single body system is not. For example Saturns rings are a stable many-body system, but if the ring was a single solid body it would be unstable and crash into the planet.
The star could have a (7)steady flow of matter falling into the star. This flow of matter could interact with the orbiting planet in a veriety of ways.
A non-orbital (8)static position could be maintained my a strong enough opposing force. A reaction involving a steady inflow of matter might be strong enough, or an intense build up of repulsive electric charge might be able to do it. The other forces listed above would probably be far to weak for this scenario.
That's 8, and I only had five ways in mind yesterday. But most importantly it could happen in some manner I haven't thought of.
Think about this: You focus on liquid water for life. Well by that standard it would be ludacris to argue that our universe could ever produce life. Our universe is 99.99999[insert twenty-five more 9's here]% empty space (yes, I checked approximately how many nines it is). And then 99.9% of the rest is stars. Our universe was created with no atoms other than hydrogen or helium. It takes a highly "improbable" process to manufacture heavy elements plus a highly "improbable" process to get those elements out of the star and into a virtually non-existant location where you can have liquid water. Based on that I'd say water based life and our universe are about the worst assumptions for getting life
Given an immensely large universe life can arise in a location with insanely rare conditions. Any explanation of how that condition could ever arise would probably sound absurd. The important thing is that given an entire universe you get a huge number of different complex situations and systems.
Whoa. For this to be any more credible than lunar green cheese, somebody would have to work out a physical system in that reference frame which is at least capable of explaining the precise properties and behaviour of quarks in our reference frame. Has this been done?
I merely said it was concievable. Given any precisely defined n-dimentional system you can always "invent" an infinite number of higher dimentional systems that will exactly produce that n-dimentional system as a surface within it. And what I described isn't that far off from "serious" physics theory. Have you ever heard of brane theory? Brane theory speculates that our universe may be a 3-d surface within a higher dimentional reality. As far as I recall they describe that surface as a plane, but putting it in terms of the surface of a sphere doesn't seem unreasonable to me.
My argument is only that though you may reason life may still be possible in most weird (to us) universes, it will still be highly improbable.
With absolutely no knowledge of what systems that universe will produce how can you conceivably say it is highly improbable? There is virtually zero water in o
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I've been enjoying this discussion so far. This seems like a good place to insert something I've been thinking. The original article emphasized that the "multiverse theory" is not scientific. I agree with that, and I expect that you do as well. The point is, however, that any theory that addresses these questions is unscientific, in the narrow sense that it is not testable. You consider these 'weird' versions of life highly improbable, but any probability distribution you could assign is surely only operative in this universe. All of your knowledge of physics, chemistry, and biology must be checked at the door. Since mathematics is not science, we might speculate that it will be of some help in this instance where science is not.
This isn't to say that I particularly like the many-worlds or many-histories theories. My objections are not scientific, but rather from the viewpoint of Occam's Razor. The essence of both of these theories is that they "multiply entities without necessity". This makes them basically ugly (see, my background is in math as well).
I'll address many-histories first. I concede that the Copenhagen hypothesis is a little rough around the edges. I haven't seen an experiment that directly supports it. Likewise, I haven't seen an experiment that could directly support the many-histories hypothesis. Different people will offer different interpretations of the various multiple slit and other experiments, but the experiments just don't support a "proof" of any of these theories. Until I see an experiment that does, I consider this a philosophical rather than a scientific question. From that standpoint, I far prefer a theory that gives a special standing to a particular part of this universe, the observer, than one that assumes the existence of uncountably many universes (where 'universe' here only indicates an environment that bounds our observations).
Since I don't like many-histories, you won't be surprised to find that I don't like many-worlds that much either. But that isn't to say that I dismiss the anthropic principle out of hand. When mystical lazy-headed people start droning on about how wonderful it is that all physical constants just happen to have the values that they do, we need something to say to shut them up. I don't see why the anthropic principle must take as its premise the existence of infinities of boring, "failed" universes. Certainly this would make the theory more interesting to the Santa Fe Institute crowd, but it just isn't necessary from the standpoint of logic. Define p as "we exist" and q as "we observe a universe with property x". Then ((q -> p) ^ q) -> (p -> q) is a tautology no matter what other universes we imagine. From the standpoint of thought or logic (which like all flavors of math is simply a device for structuring thought), the anthropic principle doesn't require many worlds and its adherents (believers?) do it no favors by dragging them into the conversation.
I submit that if we don't have something scientific to say in response to every question, that isn't a failure of science and that also isn't a situation that we haven't been in before. We might snicker at Aristotle, but his now-laughable theories did support a certain level of thought and technology for many years. It's unfortunate that they also stifled inquiry in medieval Europe. Keeping that in mind, this discussion could still be valuable, even if not scientific.
later,
Jess
p.s. When I was in college I had an argument with the house biology tutor in which he characterized the anthropic principle as "the ivy-league professoric principle". b-)
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They don't seem to in many other branches of physics. If a meteor hits the Earth, there are as many points for it to land on in Luxemborg as there are in the Pacific Ocean, but because those points don't cover as much area, the odds are greater that the ocean will be hit. How do you measure the "area" spanned by a set of possible potential universes?
What makes the situation worse is that "the set of all possible universes" doesn't look to me like something that can be constructed with the axioms of set theory; it seems more like a "set of all sets" sort of construction. However you try to describe "the set of all possible universes" S, your description will have some cardinality. You can then describe "the set of all possible universe combinations" by the power set of S, which will have a greater cardinality. But, then, doesn't "A universe consisting of this specific combination of other universes" sound like a possible universe itself? If so, then every member of that power set should map back to a member in S, which is impossible.
Sure, extra forces can be applied on purpose to rectify the orbit but there is no way for those forces to just handily appear all by themselves and give a little push at just the right point in spacetime with just the right vector.
The many-body example fails precisely because of the lack of stable orbits it is meant to address. The particles in Saturn's rings each have a stable orbit of their own to go to; in 4-space this isn't be the case. If the individual components don't have a nice gravimetric groove holding them in place then for your many body orbit to happen you need to have three or more moving objects simultaneously arrive in relative proximity each with an appropriate momentum vector. The set of such vectors is a very small subset of all those possible, so this is going to be a very rare occurrence. Bear in mind as well that with inverse cube law gravity there will be far less local concentrations of masses to play with so it will probably be very rare for three sizeable masses to even be near enough to each other to interact at all.
The whole point of a stable orbit is that it happens by itself. Your examples don't do that so I don't think they will be a factor in the evolution of life.
I do understand about the invented higher dimensional systems including e.g. a rough appreciation of eg Penrose's spinor and twistor theories. I'm not a fan; these are nothing more than fun intellectual exercises, they have yet to explain anything observable.
I do know about brane theory, though I'm not a fan of that either. I'll admit I'm prejudiced because it seems a rather ugly theory and I don't really see the point of it.
All this tells us is that life arises easily in our universe. It doesn't say anything about the fecundity of universes with no heavy elements, or no hot stars, or no room-temperature liquid polar solvents.I also do understand about emergent complexity but I was still stopped in my tracks by your impassioned examples of of tiers or nested levels of it. It reminded me strongly, for some reason, of the stunning "Wang's Carpet" chapter in Greg Egan's novel Diaspora. I have a question though relating to your specific example. Has it actually been proven that a Turing machine can be implemented using only waves in the way you suggest? Even if it has, though, there is still the very important question of whether any mechanism can exist for such a system to develop order and complexity spontaneously all by itself. Without such a mechanism the example doesn't really mean anything.
It's clear that in the absence of evidence, both of us are relying mainly on intuition to decide how easy or difficult it must be on average for interesting ordered structures to put themselves together in some arbitrary universe. We differ mainly in the degree of optimism I think.
The odd wacko aside, mainstream cosmology on the whole doesn't agree with you - the theory you are espousing is generally considered too speculative and optimistic to be really useful. That's not to say they're right and you're wrong, though. What you said about emergent complexity has made me uncomfortable about intuitive notions regarding causality and it's going to take me a while to digest that.
My 'twin' is probably using this link.
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From the scientific american article:
;)
"Space appears to be infinite in size. If so, then somewhere out there, everything that is possible becomes real, no matter how improbable it is."
My comment:
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This seems pretty familiar, you sure this isn't unquoted Hawkings or someone?
Click here or here.
Akk! Netscape crashed mid-post and I have to start from scratch. Grrr.
... they have yet to explain anything observable.
I'm afraid I was disappointed by your examples... no way for those forces to just handily appear all by themselves
I don't think you understood what I meant. Maybe I didn't explain it well enough. I was talking about forces that would in fact be inherent in the system. We were talking about a sun/planet type system. Radiation pressure is part of that system. Solar wind is part of the system. Bodies in that system will aquire a charge (earth has a large charge). If the planet gets closer to the sun each of those repulsive forces would naturaly increase. If it drifted away the forces would decrease. These kinds of forces would help hold the planet in a balanced circular orbit.
I'm guessing you may think radiation pressure would be far too weak. Radiation pressure can be great enough to overcome the gravity of a black hole. Also all sorts of scales would be entirely different in 4-d. For example I'm pretty sure a 4-d star would ignite at lower mass which would mean a lighter star. I think we are looking at orbits way smaller than in our universe.
Also realize that those forces could become highly non-linear. For example if the planet gets closer to the star it could affect the star in a manner that increases the light intensity. The force would then increase at a higher exponent of distance - the increase from being closer multiplied by the increase in brightness.
This makes me think of an additional method. If the planet affects the sun it could cause an asymetry in the radiation and/or solar wind. In the extreme case the star could be sitting right on the verge of fusion ignition. The gravity/light/heat and/or electromagnetic_field of the planet could tip the star into ignition. The fusion might only occur on the side of the sun facing the planet and might only ignite when the planet gets close enough. This would act almost like a jet engine on the star. In a less extreme example the planet might cause a minor but sufficent asymetry in the sun.
Ah, and I just thought of another solution. In 4-d gravity falls off far faster ar long range. Beyond a certian range it is effectively zero. Objects could sit at range from each other essetially forever. Any repulsive force at all would ensure the planet remains parked between stars. I know you assume life is impossible at interstellar distance from a sun in our universe, but in 4-d it may happen. Either there could be more stars, or more intense stars, or life may run on far less energy, perhaps in liquid helium.
As for the many-body suggestion, I suspect it won't work but I'm not 100% sure. Just because there's no static stable solution doesn't preclude the existance of a dynamic stable solution. I can visualise a basic 4-d orbit, but it would take tremendous work to analize the subtle intricacies of a four dimentional million-body ring system. That's a hairy problem in 3-d, much less in 4-d. Plus I'm pretty sure there's more than one kind of "ring" in 4-d.
for your many body orbit to happen you need to have three or more moving objects simultaneously arrive
The most apparent solution would be for them to form in place. The earth didn't "arrive" at the sun.
Anyway, in 4-d you probably wouldn't get conventional atoms and stars anyway. The physics would yeild radicly "things" at the lower layers. Err, did I mention that last post?
higher dimensional systems
Yeah, there's quite a few variations floating around and so far they are little more than "mind games". But they are floating around for good reason. It appears that more dimentions will lead to simpler laws of physics.
brane theory... I don't really see the point of it.
I'm pretty sure the "attaction" of the theory is that it seems like it may contain a solution to the oddities of gravity. You are probably aware that the biggest question in phy
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Obviously, I'm not multiverse expert here :) but the whole idea of an infinite number of other universes out there that exist simultaneously seems a little flawed to me.
How did everything come about as we (in this particular universe) know it? The multiverse answer is that everything possible has/or is happening in one universe or another. We just happen to be in the one were all elements worked out so that we can exist.
The problem I see with this is, the chance of everything turning out exactly the way it did in our universe, so as to allow our existence, is so small that statistically it would be called an impossibility. The multiverse idea is supposed to get rid of that impossibility. But, if we bring in an infinite number of universes to allow for every possible outcome, we also bring in at an infinite number of universes that would have had events occur within them that caused the destruction of all other universes.
Looking at this a little more, you could argue that we would also have had an infinite number of universes that were able to predict the infinite number of destructive universes and those predicting universes were able to stop them ahead of time. Phew!
But, what about the infinite number of universes that destroyed everything the instant they came about? ..... you could continue with this forever.
Seems flawed to me.
The idea of parallel universes gives me some sense of hope, simply because in one of them I must be smart enough to understand parallel universes.
I just happen to live in the one in which the wave functions collapsed into a solution of cant-do-hard-math. That sucks for this one of me.
Don't blame me, I get all my opinions from my Ouija board.
All my own work :o)
As some of you already pointed out, the universe (at least our universe) is far from being "friendly" to life. But that is actually not my whole topic for discussion.
Personally, I am afraid the NYT has been a bit to liberal with this editorial. I am not aware of how much viable physics reasoning could a professor of natural philosophy (Mr. Davies) carry, but anyhow I would strongly disagree with his claims of live being nonexistent under different dimensional and physical conditions.
If you take our rather narrow, egocentric, 3D based definition of life, it is true that this "life" would be rather hard to imagine in let's say a 7D world (how could we even image such a world at all?). But how can any of us, simple creatures who have spent their whole lifes under virtually immutable physical conditions, how can we even attempt to criticize the possibility of life existing in places of various other dimensions and physical laws (considering these would exist at all), when none of us have ever been able to simulate a usefull environment to study such alien conditions.
In this particular discussion, there are too many variables that could be changed or even disposed of to do much logical reasoning. Although I find this a rather interesting topic, it is very hard to talk about having so many unknowns.
If anyone can make any sense of my above ramblings, please reply because I got kinda lost myself...
a) Life in a 2D universe has to expend much more energy to function due to all the constraints put on it that 3D life does not have.
You are carrying in many assumptions based on human-centric view of life and physics.
Lets look at the energy levels available to run human life processeses. We run off of the chemical energy available from food, a couple of joules per gram.
But the available chemical energy is only a small fraction of the thermal energy enviornment. Thermal energy at room temperature is a couple of thousand joules per gram.
But the available thermal energy is a vanishingly small fraction of the mass-energy enviornment. Mass-energy is about 100000000000000 joules per gram. This is the energy level at which our universe actually runs. So human life runs with an efficency of something like 0.000000000001 percent of the actual energy flow of our universe.
Life is built upon a system that is built upon a system that is built upon a system that is built upon fundamental physics of the universe. The concept of energy within one system is wildly drifferent from the concept of energy is a different system. It is meaningless to draw a comparison between the energy flow in our chemical-life system and the energy flow within a some two dimentional-life system.
b) Many of the arguments made there deals with macroscopic features of such a universe...if you turn the knob on the strong nuclear force... will lead to a completely different sort of place.
Exactly, and even a single proton is a "macroscopic" object compared to our laws of physics. Our laws of function on the planck length, 10^21 times smaller than a proton I think. A proton is unimaginably huge. The concepts of mass and energy are probably meaningless at the fundamental level of our universe. A proton is 10^63 cubic plancks, a galaxy may be 10^63 atoms. A galaxy is a meaningless concept when you are looking down at the level of atoms.
If we create life or even intellegence within a computer the concepts of matter and energy could be entirely meaningless within that system. Life is a function of complexity and interactions. Our concepts of matter and energy may be entirely arbitrary internal aspects of the system we happen to live in.
I've heard this higher dimensions do not allow orbits argument somewhere before. Does anyone have some kind of reference?
It is often assumed that in 4-d space gravity would follow an inverse cube law rather than an inverse square law. That means if you dift away a little bit the gravity gets weak super fast and you drift away more and gravity falls to nothing and you drift away completely. If you drift in a little bit the gravity gets stronger super fast and you fall in a bit more and the gravity gets crazy strong and you get yanked right into the middle. It's like balancing a razorblade on its edge, a spec of dust will cause it to tip and the tip makes it tip more and it completely falls one way or the other.
Even if gravity was still an inverse square force I think there's a second problem. It's hard to explain, but I'll try. In 3-d you go around a one dimentional axis, a line. In 4-d you go around a two dimentional axis, a plane. I think when you revolve around a plane there are a whole bunch of different routes you can take and you drift freely between them. The problem is that some of these routes happen to pass through the object in the center. Eventually you'll collide at random unless there's some other force steering you away from these colisions.
Here's some images to help it make sense. In 3-d space you go around an axis, a line. Imagine that axis is a pencil. If you drop a pencil on a table there's only one way it can roll, back and forth. It can't "wiggle".
In 4-d I said you go around a 2-dimentional axis, a plane. Instead of picturing a flat sheet I want to to picture rolling it up into a sphere. A sphere is 3 dimentional, but the SURFACE of the sphere is a 2-d sheet. Now picture you d
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That used to happen to me a lot back in my Netscape 4 days. Current Mozilla (since at least 1.2) is a hell of a lot more stable.
[orbital mechanics with various forces propitiously balancing 4d gravity etc.]
Now I do see what you mean. But the inverse cube law for gravity in 4-space means that everything would have to be a lot closer. Don't know what this would mean for orbital angular momentum - everything whizzing about madly? I'm relying heavily on intuition here (you'd probably have a better chance at working out the kinetics) but it seems to me that there are just too many "ifs" involved and stable star/planet associations are going to require such a fortuitous set of circumstances that they would be rare and certainly not a common motif as they are in our universe.
you assume life is impossible at interstellar distance ... in 4-d it may happen ... there could be more ... or more intense stars,
Doubt it. With gravity acting only at relatively short range it's less likely that agglomerations of matter would form. And outer layers of candidate protostars would experience less gravity from the core so even if there was as much mass as in our own sun it still might not squash down enough to start fusion (there's just too much I don't know about this...this discussion is already well into territory where we need to start doing back-of-envelope calculations).
or life may run on far less energy, perhaps in liquid helium.
Things would progress very slowly and there would probably be insufficient energy and materials around for intelligent life to evolve (there'd be nothing to do and nothing to do it with so there's no point in involving intelligence, from the infortunate helium-dwelling species' point of view).
the subtle intricacies of a four dimentional million-body ring system.... That's a hairy problem
In 3-space each particle's path is largely dictated by its own inertia and the curved space around the gravitational well. Slight deviations caused by encounters with other particles of similar size don't immediately throw the particle out into a drastically different orbit because the gravitational field is relatively uniform across significant distances. In 4-space the gravitational well is extremely steep if you are close enough to feel it at all. It's a bit like Hawking radiation...even a slight deviation in the particle's path would cause it to either plummet down the well or drift away. A ring system in 4-space would disperse within a very much shorter time than it would here (even Saturn's brilliant ring system will not last forever).
Anyway, in 4-d you probably wouldn't get conventional atoms and stars anyway. The physics would yeild radicly "things" at the lower layers.
But we can't talk about that.
Brane theory...how to reconcile gravity with the rest of physics.
I know GUTs. I think some of the theories developed from string theory are promising. Brane theory sucks. In my opinion.
[Greg Egan's novel "Diaspora"]
Diaspora is about a sentient computer -generated being who leaves its VR world in a robot body and takes a very very long journey indeed. The "Wang's carpet" chapter is about a floating mat they find on an oceanic world which is constructed out of molecules that behave like Wang's tiles. It's a Turing machine, growing at the edges by accretion, and ...well I don't want to spoil it. As well as the rock-hard theoretical scientific angle, it's a very touching story even though the main character is artificial.
I think I know what floats your boat by know and I can guarantee that most of Egan's novels would blow you away completely. Even more than Diaspora you really must read Permutation City. It's just jaw-dropping. It's heavily inspired by Hans Moravec's w
Philosophy students ridicule it too. That's where I heard it. In fact, I've since discovered that it is intentionally ridiculous. As such, it was unfair to call it a classic of metaphysics.
l
The phrase appears to originate in ridicule of St. Thomas Aquinas. To say that Aquinas was addressing matters of conciousness in general is generous. He wrote in particular about the nature of angels.
Phrase origin at:
http://www.straightdope.com/classics/a4_132.htm
Thomas Aquinas on _Whether an Angel is Altogether Incorporeal_ at:
http://www.newadvent.org/summa/105001.htm
Perhaps I should have said: "The mockery of metaphysics 'How many angels can dance on the head of a pin?' is the canonical meaningless question." That is less kind to metaphysics than I meant to be, though. My intention was not to insult metaphysics, but to argue that religion does not illuminate science. By using that phrase, I inadvertently insulted those most likely to disagree with me.
Assembly is the reverse of disassembly.
I moved this to the top because I think it may bring a crucial insight:
:D
is it physically possible to make a replicator out of waves
You're still being blinded by assumptions based on human experience. I'm sure you're familiar with the basic concepts of quantum mechanics, there is no difference between particles and waves. Light behaves like a particle. Electrons behave like waves. "Waves" are a high level emergent phenomena. They don't exist!
Quantum mechanics and relativity are "hard" and "confusing" exactly because it is so hard to drop our basic assumptions about how the world works. At the quantum/relativistic levels all of our concepts become either entirely meaningless, or need to be radically revised. Matter = energy = particles = waves. Space = time. I strongly suspect spacetime is also equal to matter and energy. Heisenberg uncertainty says that position and momentum do not simultaneously exist. The same goes for time and energy.
If matter, energy, particles, waves, space, time, position, and momentum all lose their usual meanings at other layers in our own universe why should they be meaningful in a different universe?
Without a set of equations to analize we are rather limited in what we can say about some other universe, but I think the concept of systems still applies. We can study systems in general and there are some things we can prove about systems.
Let me clarify just how far human life is removed from the foundation of our universe. (Note, I already had most of these figures handy from some other posts I made recently.)
Energy:
We run off of the chemical energy available from food, a couple of joules per gram. That is only a small fraction of the thermal energy of our enviornment. Room temperature thermal energy is a couple of thousand joules per gram. Thermal energy is a vanishingly small fraction of the mass-energy enviornment. Mass-energy is about 100000000000000 joules per gram. This is the energy level at which our universe actually runs. So human life runs with an efficency of something like 0.000000000001 percent of the actual energy flow of our universe.
It is meaningless to say there would not be enough energy available for life. The energy life has available is an entirely subjective concept of the emergent system it is running within.
Time:
The base time unit of our universe is planck time, 10^-43 seconds. So we run at 0.00000000000000000000000000000000000000001% of the timescale of our universe. It is meaningless to say life would run too slow. Time is going to be an entirely subjective concept of the emergent system it is running within.
Size:
Forget the size of a human, lets look at the size of a proton. The fundamental unit of distance in our universe is the planck length, 10^-35 meters. That is 10^20 times smaller than the diameter of a proton. A proton is a 3 dimentional object, so a single proton is 10^60 cubic plancks. The Milkyway galaxy is 10^60 cubic meters. A proton could be an emergent structure just as random inside as a galaxy. A galaxy is a mostly empty thing with entirely random lumps inside.
Lets imagine our universe is actually running on a 3 dimentional version of Conway's life. It takes 10^60 cells to represent a single proton. A proton doesn't have a well ordered design inside like a car, it is a random lumpy mish-mash like a galaxy. The volume of the universe is 10^183 cubic planks. You have to run 10^43 time ticks to produce one second. The age of the universe is 10^61 time ticks. That's what I meant when I said that time and space of a universe were essentially infinite. It also shows that causality is so far down at the bottom that it is entirely divorced from the life level.
You made objections based on the rarity of events. Well, lets look for liquid water in our universe. I'll assume every solar system has an earth. Water is 0.01% of the earth's mass. The earth is 0.0003% of the solar system's mass. All but about 0.00000
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I'm well aware of all that but I don't draw the same conclusions, obviously.
Also you kind of glossed over the answer to my question about whether waves could be used to make replicators. I see nothing proven about this.
Your speculations about mass,energy,space,time etc are only half right. For starters, mass != energy. There is an equivalence but not an equality. Otherwise there would be no distinction. If your mass were to suddenly become indistinguishable from energy we'd all be the worse for it :o\
Space and time are interrelated in the equations of GR, and even potentially interchangeable in the exotic equations attempting to analyze spacetime near a singularity, but this is not so in QM. Time and space are clearly not identical and in fact the very nature of time is still very much a matter for speculation even as far as conventional physicists are concerned.
It's misleading to claim they "lose their usual meanings" at other layers when they are fundamental quantities which apply right down to the quark level and maybe even below that. There may be wave particle duality and measurement may become a matter of statistics, but particles do have mass, position and momentum nonetheless. Speculation about universes without space, time, mass, energy etc. at any level has little to do with physics. It becomes indistinguishable from philosophy or mysticism.[Examples of differences of scale] The extremes aren't automatically habitable.
That isn't Egan's fault, the idea comes from Hans Moravec (whose relevant writings are available online). He poses some very interesting questions about the nature of self, consciousness, existence etc. The argument about the continuation of an externally terminated world line does actually make sense in the context of Many Worlds, both in Moravec's original theory and in Egan's story. Ping me back if you want me to explain.
Tipler is one of the top GR physicists in the world. He co-authored The Anthropic Cosmological Principle with John D Barrow. Yes, his Omega Point theory is nothing more than Science Fiction but it does at least contain very interesting physics - and you and he do seem to agree about most things ;o)
Ha! - here's yet more proof you're getting carried away with your own wild speculations instead of paying attention to what I am saying. I was talking about the first replicators. By definition these arose from non-replicators in a single step. The first replicators in our locality were not "humans", they were probably short segments of RNA or something of that nature.
Yes. Funny, that. I wonder why? (/irony) Maybe because that level of complexity (atomic matter, complex chemistry, a compatible temperature range) was actually necessary for the next higher level - life - to be supported. Let's not lose sight of what the only extant example is telling us. And bear in mind the Copernican principle of mediocrity - which should carry some weight at least.
BTW, Any idea how long a story thread stays open for comment posting?
Also you kind of glossed over the answer to my question about whether waves could be used to make replicators. I see nothing proven about this.
:D
You're pretty knowledgable about science, I guess I assumed you were more familiar with the "oddities" of quantum mechanics.
Two "waves" of light that can in fact interact. We don't see this effect in everyday life because visible is far too low in energy to equal even the lightest stable mass. Two high energy photons can collide resulting in matter and antimatter exactly the same way that matter and antimatter can collide resulting in photons.
Light seems like a non-interacting wave only because of the narrow limits of human experience.
For starters, mass != energy. There is an equivalence but not an equality.
Matter and energy really are different views of the same thing. Light waves with enough energy can "collide" and reconfigure into any particle. It is merely a change of shape or pattern. Matter is merely a lightwave that is tied up in a knot. ("knot" being figurative)
There may be wave particle duality and measurement may become a matter of statistics, but particles do have mass, position and momentum nonetheless.
That is a common missunderstanding of quantum mechanics. Einstein himself tried to argue exactly that position. It was known as the Bohr-Einstein debate. Einstein lost. It is not an issue of statistics. It is not an imprecision in measurement. Quantum mechanics says there is no point-like particle. Quantum mechanics says those values do not exist.
Things are different on the quantum layer of our universe. Common sence fails us and leads us to false conclusions. Fundamental concepts like the position of a particle really do lose their meaning.
Duality means that you don't have two things, you really have one thing. That thing is often reffered to as a wavicle. In some ways a wavicle resembles our concept of a wave, and in some ways it resembles a particle, but it is different from either. The concepts of particles and waves cease to apply on the quantum scale, everything is a "wavicle". Light is a wavicle, electrons are wavicles, everything is a wavicle.
The beauty of fundamental physics is simplification and unification. Light/electric force/magnetic force are all really different aspects of electromagnetism. The strong force and the weak force have been shown to be the same as electromagnetism. Once they can unify gravity there will only be force in the universe. And as I mentioned earlier matter is merely a localized knot of that force.
Our entire universe is really just once thing acting on itself in a simple yet rich manner. Everything in the universe is emergent from that unitary base.
Speculation about universes without space, time, mass, energy etc. at any level has little to do with physics. It becomes indistinguishable from philosophy or mysticism.
Welcome to the bizzare world of quantum mechanics and beyond
[Examples of differences of scale] The extremes aren't automatically habitable.
Nothing is "extreme" unless you compare it to something else. You are making an anthropomorphic assumption of scale. Our universe has 60 (or more) orders of magnitude of scale available. Life could show up at whatever level it finds convient and habitable.
Ha! - here's yet more proof you're getting carried away with your own wild speculations instead of paying attention to what I am saying.
Either I didn't phrase my answer clearly or you missread me.
I was talking about the first replicators.
I pointed to humans with the implication that that they were decended from "first replicators".
By definition these arose from non-replicators in a single step. The first replicators in our locality were not "humans", they were probably short segments of RNA or something of that nature.
Right, and they spontaneously appeared o
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*sigh* Mozilla crashed and ate my detailed reply. I haven't the heart to type it all in again. So here's the shorthand blockquote-free version (my apologies if it appears a bit curt, it's late and I have to get to bed :o\ ):
Your arguments, where they attempt to rely on physics, are strictly pop-sci, littered with implausible and incorrect layman-friendly analogies and accompanied by several diversionary straw men. (I'm trying not to say 'barely sophomoric', but you do tend to labour the most basic points with which everybody with a first-year college science education is already well acquainted. eg. that stuff about wavicles, force unification and symmetry breaking.)
For example:
1) We all know particles can spontaneously "freeze" out of energy, but this doesnt help your argument (which was: that an energy-only universe can contain waves which form replicators). If you have to invoke matter then you already gave up on your own argument.
(Also: To talk of photons colliding is nonsense. Photons are packets of EM energy; they don't "collide", they interfere. *IF* the interference produces a wave amplitude that is near enough in energy to the rest mass of a relatively stable particle-antiparticle pair, there is a calculable probability that such a pair will be formed with the excess energy being carried away in the form of those particles' individual momenta with opposite signs - this rapid separation being the only thing that prevents them from immediately annihilating each other.)
2) It's disingenous to suggest that Bohr won the *entire* argument. We still need classical mechanics, and it still works as a method even at small scales once you take uncertainty into the picture. In fact, the point-like particle not only exists, there are some types of experiment where it's all you get to see. That's why we have duality and not just "wavality".
3) Matter and energy are not "views" of the same thing - there is an objectively real state change involved. It's true that QM says material objects can be viewed as a wave, but I think you may be confusing the energy waves that exist in eg. EM radiation, with the probability waves associated with a particle's position or momentum QM. They are not the same thing at all. The former are oscillations in a field of force, with a specific and measurable spatial extent, and which are always forced to propagate at the speed of light. The latter are standing waves indicating a probability distribution in some abstract mathematical space - which in the single unique and specific case of the "position" property, happens to map simply onto the spatial coordinates of our universe. The probability wave associated with (for example) momentum does not.
4) Our universe hosts or has hosted/will host 60 orders of magnitude of physical conditions from one extreme to the other- but ordered, dynamic structures (life) do not have to be able to exist in the whole range, it's only you that's saying that they do - insistently enough that it appears to be axiomatic for you! But it's not an objective position to argue from. Life will appear where "convenient", yes, but some times/places have to be more "convenient" than others in order for the probability of a given event to be maximized. *That* is axiomatic for me, if you like.
5) The first replicators here were indeed spontaneous but this single *extant* (i.e. what evidence we have to hand) example may have benefited from favourable local circumstances. There's no evidence to suggest it should happen everywhere. On the contrary, if we are to assume that life often progresses toward intelligence, civilization & therefore manipulation of the environment then we have to answer the paradox Enrico Fermi found in the Drake equation.
Finally as regards your claim that QM is bizarre - actually I find QM quite rational and satisfying. But then, I don't try to make QM responsible for everything including things we haven't even observed to be true. It's only a model (shh!)
Finally as regards your claim that QM is bizarre - actually I find QM quite rational and satisfying
Ahh, that explains the problem.
"Anyone who is not shocked by quantum theory has not understood it." - Niels Bohr
"I think I can safely say that nobody understands Quantum Mechanics" - Richard P. Feynman
quantum mechanics bizzare 8910 hits. If you don't think QM is bizarre then you're only familiar with simplified and erroneous pop-sci explanations of QM.
Your arguments, where they attempt to rely on physics, are strictly pop-sci, littered with implausible and incorrect layman-friendly analogies
To paraphrase Clarke's Law, any sufficiently advanced science is indistiguishable from nonsense. I'll try to include some authoritative links to prove I'm getting it right. I'm saying bizarre stuff because QM really is bizarre.
To talk of photons colliding is nonsense. Photons are packets of EM energy; they don't "collide"
"An International Conference on The Structure and Interactions of the Photon Including the 14th International Workshop on Photon-Photon Collision"
Packets of EM energy really can collide. Just because it is "nonsense" doesn't mean it isn't true.
It's disingenous to suggest that Bohr won the *entire* argument.
Really? And exactly where in the Bohr-Einstein debate did Einstein do anything other than concede?
We still need classical mechanics
It's still useful on a higher emergent level, but is is simply wrong down on the quantum level. Just like Newtonian mechanics are useful on the human scale, but completely wrong when you look at high speeds.
In fact, the point-like particle not only exists
No, according to quantum mechanics the concepts of particles and waves are both wrong. The idea that an electron is a particle with a real position is completely incompatible with the "double slit" "single electron" experiment. There is no way a point-like particle with an actual position value can go through two different slits at the same time.
Point-like particles do not exist. Just because it is "nonsense" does not make it wrong.
The photoelectric effect proves that light isn't really a wave. Just because it is nonsense to say light isn't a wave doesn't make it wrong.
Wave and particle descriptions may be useful at times, but they are both fundamentally incorrect. You are trying to use duality to glue together two broken models. Duality means you really have one thing, and it is neither particle nor wave. It is something else. It is something bizarre and nonsensical.
the point-like particle not only exists, there are some types of experiment where it's all you get to see.
Yeah, there are some types of experiments where you put an elephants trunk on a table and all you get to see looks like a snake. Just because some experiments say an elephant resembles a snake doesn't mean an elephant is a snake.
There are experiments that prove electrons aren't particles. The particle model is useful at times, but it is wrong.
Matter and energy are not "views" of the same thing
If you allow me to assume string theory, the only difference between a particle and a light wave is a difference in direction.
Imagine a garden hose. Light would be a wave moving along the hose at the speed of light. A particle would be a wave going around the hose at the speed of light. A wave going around the hose would be a stationary stand
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quantum mechanics bizzare [google.com] 8910 hits.
Yes, of course it's bizarre to most people because it is counter-intuitive to those people whose entire experience of the world is classical and who haven't devoted a great deal of time trying to understand QM to any meaningful depth. A google search on "roswell ufo" yields more than ten times that number of hits but it doesn't mean there were really any flying saucers at roswell. A match count on google for any gee-whiz phrase is only a measure of laymen's preconceptions, not a guarantee of truth.
To paraphrase Clarke's Law, any sufficiently advanced science is indistiguishable from nonsense.
That's your opinion only. I don't think you would get many professional scientists to agree with you. As a bunch they're notably averse to science that's indistinguishable from nonsense.
Packets of EM energy really can collide.
The papers themselves don't seem to be online but OK I'll grant you that the collider people do tend to use the term "collisions", most likely because they happen to be using a collider to get sufficient energy into a small enough volume. I do still think "collide" is as poor choice of word because of the mechanism involved though. You yourself quite early in this discussion mentioned the propensity of waves to pass through one another (interacting briefly en-route). EM waves with sufficient energy, which can be produced during constructive interference, may give up mass. But this actually happens wherever sufficient energy appears. It could originate from a single emission, there doesn't even have to be two waves, let alone two waves with different vectors. Even if "collision" might be redefined to apply to ghosts passing through one another without any change in vector (in fact even if the post-event photons' trajectories were altered as a result of the interaction) it would still be incidental to the conversion process.
according to quantum mechanics the concepts of particles and waves are both wrong. The idea that an electron is a particle with a real position is completely incompatible with the "double slit" "single electron" [google.com] experiment.
Heh! Yes, and the idea that an electron is a probability distribution is completely incompatible with the Millikan oil drop experiment where the electron is clearly either in the oil droplet or outside it. Or any experiment where particle interactions are observed. The fact is that you can't dispense with either model.
[I think you can dispense, though, with the google links for basic high school experiments, I doubt anybody would be reading this who isn't already familiar with them. In any conversation some things have to be treated as "given"]
Point-like particles do not exist...[and neither do waves]
I don't really know what you are trying to say here. You appear to contradict yourself several times and then contradict the contradiction. I know that duality is basically handwaving but so what? Despite its stubborn refusal to frame itself in simple terms easy for humans to understand, QM has nevertheless been described as the most successful physical theory of all time (because of its predictive power). Internal contradictions notwithstanding.
If you allow me to assume string theory
Well, that would be allowing a lot! I happen to like string theory mysel
Apropos of something we were talking about earlier (Permutation City) I found this tonight - quite amusing...
Chuckle. I'd rather have two of me with £10,000 pensions than one of me with a £12,500 pension :)
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your patronizing remark
:)
... Internal contradictions
I hate being patronized more than almost anything else.
My comment was intentional minor dig, you were far more patronizing to me in your previous post. I understand you were frustrated having to re-write the post from scratch, but you did let it slip in.
Sorry if I over did it with the "basic physics" and links, you accused me of "attempting" to be based on physics, "pop-sci", "implausible and incorrect layman-friendly analogies". You thought I wasn't talking valid science so I attempted to re-ground my position in physics we could both agree on. Maybe I over-compensated
In text chat it's hard to know what the other person is familiar with and what he isn't. It's hard to know which ideas I successfully communicated and which I didn't.
>quantum mechanics bizzare [google.com]
only a measure of laymen's preconceptions
Did you look at the sources of the hits? They are from universities, physics institutions, and PhD's. The second hit is AIP, American Institute of Physics. The best physists in the world commonly reffer to QM as bizarre.
You appear to contradict yourself several times and then contradict the contradiction.
If that's how it appears then we have a communication problem. I see no contradictions in what I said. Unfortunately you didn't point out a specific contradiction, or if you did I missed it.
I said that the particle model is wrong. I said the wave model is wrong. I said that quantum mechanics is based on something else. In some ways that "something else" can resemble a particle or a wave, but it isn't either. It has "bizarre" properties entirely alien to human-level experience. I don't see the contradiction.
QM
QM doesn't HAVE internal contradictions.
This is probably why you think I was contradicting myself and belaboring "bizarreness". What you think are "contradictions" in QM are perfectly consistant. They are just entirely alien (bizarre).
If you try to impose concepts like particles and waves on QM you get contradictions. Understanding QM isn't impossible, but it does require escaping all sorts of fundamental assumptions about how the universe works. Common sense is the biggest obstacle to understanding QM.
I do still think "collide" is as poor choice of word
They use that word because it is the most accurate word they have. Scientists tend to be obsessive about their choice of terms.
Not only can light collide with light, but matter can not-collide with matter. In a Bose-Einstein Condensate matter can pass through matter just like light usually passes through light.
It could originate from a single emission, there doesn't even have to be two waves
I'm not certain, but I think a single light emission converting into a particle(s) would violate some conservation law. You could have one double energy photon interact with a second arbitrarily low energy photon though. You would then look at it in a moving refference frame where the two photons had equal energy.
let alone two waves with different vectors.
If the photons aren't colliding head-on they would need higher energy because you'd probably look at them from a moving refference frame where they were colliding head-on.
Yes, and the idea that an electron is a probability distribution is completely incompatible with the Millikan oil drop experiment where the electron is clearly either in the oil droplet or outside it.
No incompatibility. Your error is is to say "the electron is clearly either in the oil droplet or outside it". First of all everything making up the drop is just as distributed as the electron. Second, even if you assumed a clearly defined border for the oil drop the electron distribution is not confined by that border. An electron 50% inside and 50% outside that border will have a 50% chance of exerting a
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